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Mohsen JJ, Mohsen MG, Jiang K, Landajuela A, Quinto L, Isaacs FJ, Karatekin E, Slavoff SA. Cellular function of the GndA small open reading frame-encoded polypeptide during heat shock. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.29.601336. [PMID: 38979229 PMCID: PMC11230408 DOI: 10.1101/2024.06.29.601336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Over the past 15 years, hundreds of previously undiscovered bacterial small open reading frame (sORF)-encoded polypeptides (SEPs) of fewer than fifty amino acids have been identified, and biological functions have been ascribed to an increasing number of SEPs from intergenic regions and small RNAs. However, despite numbering in the dozens in Escherichia coli, and hundreds to thousands in humans, same-strand nested sORFs that overlap protein coding genes in alternative reading frames remain understudied. In order to provide insight into this enigmatic class of unannotated genes, we characterized GndA, a 36-amino acid, heat shock-regulated SEP encoded within the +2 reading frame of the gnd gene in E. coli K-12 MG1655. We show that GndA pulls down components of respiratory complex I (RCI) and is required for proper localization of a RCI subunit during heat shock. At high temperature GndA deletion (ΔGndA) cells exhibit perturbations in cell growth, NADH+/NAD ratio, and expression of a number of genes including several associated with oxidative stress. These findings suggest that GndA may function in maintenance of homeostasis during heat shock. Characterization of GndA therefore supports the nascent but growing consensus that functional, overlapping genes occur in genomes from viruses to humans.
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Affiliation(s)
- Jessica J. Mohsen
- Department of Chemistry, Yale University, New Haven, CT 06511
- Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT 06516
| | - Michael G. Mohsen
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06511
| | - Kevin Jiang
- Department of Chemistry, Yale University, New Haven, CT 06511
- Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT 06516
| | - Ane Landajuela
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510
- Nanobiology Institute, Yale University, West Haven, CT 06516
| | - Laura Quinto
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
- Systems Biology Institute, Yale University, West Haven, CT 06516
| | - Farren J. Isaacs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
- Systems Biology Institute, Yale University, West Haven, CT 06516
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510
- Nanobiology Institute, Yale University, West Haven, CT 06516
- Wu Tsai Institute, Yale University, New Haven, CT 06511
- Université de Paris, Saints-Pères Paris Institute for the Neurosciences (SPPIN), Centre National de la Recherche Scientifique (CNRS), 75006 Paris, France
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
| | - Sarah A. Slavoff
- Department of Chemistry, Yale University, New Haven, CT 06511
- Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT 06516
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
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2
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Chen Z, Yu S, Liu J, Guo L, Wu T, Duan P, Yan D, Huang C, Huo Y. Concentration Recognition-Based Auto-Dynamic Regulation System (CRUISE) Enabling Efficient Production of Higher Alcohols. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2310215. [PMID: 38626358 PMCID: PMC11187965 DOI: 10.1002/advs.202310215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/12/2024] [Indexed: 04/18/2024]
Abstract
Microbial factories lacking the ability of dynamically regulating the pathway enzymes overexpression, according to in situ metabolite concentrations, are suboptimal, especially when the metabolic intermediates are competed by growth and chemical production. The production of higher alcohols (HAs), which hijacks the amino acids (AAs) from protein biosynthesis, minimizes the intracellular concentration of AAs and thus inhibits the host growth. To balance the resource allocation and maintain stable AA flux, this work utilizes AA-responsive transcriptional attenuator ivbL and HA-responsive transcriptional activator BmoR to establish a concentration recognition-based auto-dynamic regulation system (CRUISE). This system ultimately maintains the intracellular homeostasis of AA and maximizes the production of HA. It is demonstrated that ivbL-driven enzymes overexpression can dynamically regulate the AA-to-HA conversion while BmoR-driven enzymes overexpression can accelerate the AA biosynthesis during the HA production in a feedback activation mode. The AA flux in biosynthesis and conversion pathways is balanced via the intracellular AA concentration, which is vice versa stabilized by the competition between AA biosynthesis and conversion. The CRUISE, further aided by scaffold-based self-assembly, enables 40.4 g L-1 of isobutanol production in a bioreactor. Taken together, CRUISE realizes robust HA production and sheds new light on the dynamic flux control during the process of chemical production.
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Affiliation(s)
- Zhenya Chen
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
- Tangshan Research InstituteBeijing Institute of Technology, No. 57, South Jianshe Road, Lubei DistrictTangshanHebei063000China
| | - Shengzhu Yu
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Jing Liu
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Liwei Guo
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Tong Wu
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Peifeng Duan
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Dongli Yan
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Chaoyong Huang
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
| | - Yi‐Xin Huo
- Key Laboratory of Molecular Medicine and BiotherapyAerospace Center HospitalSchool of Life ScienceBeijing Institute of TechnologyHaidian DistrictNo. 5 South Zhongguancun StreetBeijing100081China
- Tangshan Research InstituteBeijing Institute of Technology, No. 57, South Jianshe Road, Lubei DistrictTangshanHebei063000China
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3
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Hoffman T, Kinne J, Cho KH. Pro-SMP finder-A systematic approach for discovering small membrane proteins in prokaryotes. PLoS One 2024; 19:e0299169. [PMID: 38422081 PMCID: PMC10903887 DOI: 10.1371/journal.pone.0299169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024] Open
Abstract
Prokaryotic chromosomes contain numerous small open reading frames (ORFs) of less than 200 bases. Since high-throughput proteomics methods often miss proteins containing fewer than 60 amino acids, it is difficult to decern if they encode proteins. Recent studies have revealed that many small proteins are membrane proteins with a single membrane-anchoring α-helix. As membrane anchoring or transmembrane motifs are accurately identifiable with high confidence using computational algorithms like Phobius and TMHMM, small membrane proteins (SMPS) can be predicted with high accuracy. This study employed a systematic approach, utilizing well-verified algorithms such as Orfipy, Phobius, and Blast to identify SMPs in prokaryotic organisms. Our main search parameters targeted candidate SMPs with an open reading frame between 60-180 nucleotides, a membrane-anchoring or transmembrane region 15 and 30 amino acids long, and sequence conservation among other microorganisms. Our findings indicate that each prokaryote possesses many SMPs, with some identified in the intergenic regions of currently annotated chromosomes. More extensively studied microorganisms, such as Escherichia coli and Bacillus subtilis, have more SMPs identified in their genomes compared to less studied microorganisms, suggesting the possibility of undiscovered SMPs in less studied microorganisms. In this study, we describe the common SMPs identified across various microorganisms and explore their biological roles. We have also developed a software pipeline and an accompanying online interface for discovering SMPs (http://cs.indstate.edu/pro-smp-finder). This resource aims to assist researchers in identifying new SMPs encoded in microbial genomes of interest.
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Affiliation(s)
- Tara Hoffman
- Department of Math and Computer Science, Indiana State University, Terre Haute, Indiana, United States of America
| | - Jeff Kinne
- Department of Math and Computer Science, Indiana State University, Terre Haute, Indiana, United States of America
| | - Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, Indiana, United States of America
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Blaimschein N, Parameswaran H, Nagler G, Manioglu S, Helenius J, Ardelean C, Kuhn A, Guan L, Müller DJ. The insertase YidC chaperones the polytopic membrane protein MelB inserting and folding simultaneously from both termini. Structure 2023; 31:1419-1430.e5. [PMID: 37708891 PMCID: PMC10840855 DOI: 10.1016/j.str.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/22/2023] [Accepted: 08/18/2023] [Indexed: 09/16/2023]
Abstract
The insertion and folding of proteins into membranes is crucial for cell viability. Yet, the detailed contributions of insertases remain elusive. Here, we monitor how the insertase YidC guides the folding of the polytopic melibiose permease MelB into membranes. In vivo experiments using conditionally depleted E. coli strains show that MelB can insert in the absence of SecYEG if YidC resides in the cytoplasmic membrane. In vitro single-molecule force spectroscopy reveals that the MelB substrate itself forms two folding cores from which structural segments insert stepwise into the membrane. However, misfolding dominates, particularly in structural regions that interface the pseudo-symmetric α-helical domains of MelB. Here, YidC takes an important role in accelerating and chaperoning the stepwise insertion and folding process of both MelB folding cores. Our findings reveal a great flexibility of the chaperoning and insertase activity of YidC in the multifaceted folding processes of complex polytopic membrane proteins.
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Affiliation(s)
- Nina Blaimschein
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, 4058 Basel, Basel-Stadt, Switzerland
| | - Hariharan Parameswaran
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Gisela Nagler
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Baden-Württemberg, Germany
| | - Selen Manioglu
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, 4058 Basel, Basel-Stadt, Switzerland
| | - Jonne Helenius
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, 4058 Basel, Basel-Stadt, Switzerland
| | | | - Andreas Kuhn
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Baden-Württemberg, Germany
| | - Lan Guan
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, 4058 Basel, Basel-Stadt, Switzerland.
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5
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Yokoyama T, Yamagata Y, Honna S, Mizuno S, Katagiri S, Oi R, Nogi T, Hizukuri Y, Akiyama Y. S2P intramembrane protease RseP degrades small membrane proteins and suppresses the cytotoxicity of intrinsic toxin HokB. mBio 2023; 14:e0108623. [PMID: 37409810 PMCID: PMC10470546 DOI: 10.1128/mbio.01086-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 05/25/2023] [Indexed: 07/07/2023] Open
Abstract
The site2-protease (S2P) family of intramembrane proteases (IMPs) is conserved in all kingdoms of life and cleaves transmembrane proteins within the membrane to regulate and maintain various cellular activities. RseP, an Escherichia coli S2P peptidase, is involved in the regulation of gene expression through the regulated cleavage of the two target membrane proteins (RseA and FecR) and in membrane quality control through the proteolytic elimination of remnant signal peptides. RseP is expected to have additional substrates and to be involved in other cellular processes. Recent studies have shown that cells express small membrane proteins (SMPs; single-spanning membrane proteins of approximately 50-100 amino acid residues) with crucial cellular functions. However, little is known about their metabolism, which affects their functions. This study investigated the possible RseP-catalyzed cleavage of E. coli SMPs based on the apparent similarity of the sizes and structures of SMPs to those of remnant signal peptides. We screened SMPs cleaved by RseP in vivo and in vitro and identified 14 SMPs, including HokB, an endogenous toxin that induces persister formation, as potential substrates. We demonstrated that RseP suppresses the cytotoxicity and biological functions of HokB. The identification of several SMPs as novel potential substrates of RseP provides a clue to a comprehensive understanding of the cellular roles of RseP and other S2P peptidases and highlights a novel aspect of the regulation of SMPs. IMPORTANCE Membrane proteins play an important role in cell activity and survival. Thus, understanding their dynamics, including proteolytic degradation, is crucial. E. coli RseP, an S2P family intramembrane protease, cleaves membrane proteins to regulate gene expression in response to environmental changes and to maintain membrane quality. To identify novel substrates of RseP, we screened small membrane proteins (SMPs), a group of proteins that have recently been shown to have diverse cellular functions, and identified 14 potential substrates. We also showed that RseP suppresses the cytotoxicity of the intrinsic toxin, HokB, an SMP that has been reported to induce persister cell formation, by degrading it. These findings provide new insights into the cellular roles of S2P peptidases and the functional regulation of SMPs.
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Affiliation(s)
- Tatsuhiko Yokoyama
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Yutaro Yamagata
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Saisei Honna
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Shinya Mizuno
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Shizuka Katagiri
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama, Japan
| | - Rika Oi
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama, Japan
| | - Terukazu Nogi
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama, Japan
| | - Yohei Hizukuri
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Yoshinori Akiyama
- Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
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6
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Sarmah P, Shang W, Origi A, Licheva M, Kraft C, Ulbrich M, Lichtenberg E, Wilde A, Koch HG. mRNA targeting eliminates the need for the signal recognition particle during membrane protein insertion in bacteria. Cell Rep 2023; 42:112140. [PMID: 36842086 PMCID: PMC10066597 DOI: 10.1016/j.celrep.2023.112140] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 01/10/2023] [Accepted: 02/02/2023] [Indexed: 02/26/2023] Open
Abstract
Signal-sequence-dependent protein targeting is essential for the spatiotemporal organization of eukaryotic and prokaryotic cells and is facilitated by dedicated protein targeting factors such as the signal recognition particle (SRP). However, targeting signals are not exclusively contained within proteins but can also be present within mRNAs. By in vivo and in vitro assays, we show that mRNA targeting is controlled by the nucleotide content and by secondary structures within mRNAs. mRNA binding to bacterial membranes occurs independently of soluble targeting factors but is dependent on the SecYEG translocon and YidC. Importantly, membrane insertion of proteins translated from membrane-bound mRNAs occurs independently of the SRP pathway, while the latter is strictly required for proteins translated from cytosolic mRNAs. In summary, our data indicate that mRNA targeting acts in parallel to the canonical SRP-dependent protein targeting and serves as an alternative strategy for safeguarding membrane protein insertion when the SRP pathway is compromised.
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Affiliation(s)
- Pinku Sarmah
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Wenkang Shang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University Freiburg, 79104 Freiburg, Germany
| | - Maximilian Ulbrich
- Internal Medicine IV, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | | | - Annegret Wilde
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
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7
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Bogati B, Shore SFH, Nipper TD, Stoiculescu O, Fozo EM. Charged Amino Acids Contribute to ZorO Toxicity. Toxins (Basel) 2022; 15:32. [PMID: 36668852 PMCID: PMC9860968 DOI: 10.3390/toxins15010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 12/24/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Chromosomally encoded toxin-antitoxin systems have been increasingly identified and characterized across bacterial species over the past two decades. Overproduction of the toxin gene results in cell growth stasis or death for the producing cell, but co-expression of its antitoxin can repress the toxic effects. For the subcategory of type I toxin-antitoxin systems, many of the described toxin genes encode a small, hydrophobic protein with several charged residues distributed across the sequence of the toxic protein. Though these charged residues are hypothesized to be critical for the toxic effects of the protein, they have not been studied broadly across different type I toxins. Herein, we mutated codons encoding charged residues in the type I toxin zorO, from the zor-orz toxin-antitoxin system, to determine their impacts on growth inhibition, membrane depolarization, ATP depletion, and the localization of this small protein. The non-toxic variants of ZorO accumulated both in the membrane and cytoplasm, indicating that membrane localization alone is not sufficient for its toxicity. While mutation of a charged residue could result in altered toxicity, this was dependent not only on the position of the amino acid within the protein but also on the residue to which it was converted, suggesting a complex role of charged residues in ZorO-mediated toxicity. A previous study indicated that additional copies of the zor-orz system improved growth in aminoglycosides: within, we note that this improved growth is independent of ZorO toxicity. By increasing the copy number of the zorO gene fused with a FLAG-tag, we were able to detect the protein expressed from its native promoter elements: an important step for future studies of toxin expression and function.
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Affiliation(s)
| | | | | | | | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, USA
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8
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Proctor MS, Morey-Burrows FS, Canniffe DP, Martin EC, Swainsbury DJK, Johnson MP, Hunter CN, Sutherland GA, Hitchcock A. Zeta-Carotene Isomerase (Z-ISO) Is Required for Light-Independent Carotenoid Biosynthesis in the Cyanobacterium Synechocystis sp. PCC 6803. Microorganisms 2022; 10:microorganisms10091730. [PMID: 36144332 PMCID: PMC9505123 DOI: 10.3390/microorganisms10091730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
Carotenoids are crucial photosynthetic pigments utilized for light harvesting, energy transfer, and photoprotection. Although most of the enzymes involved in carotenoid biosynthesis in chlorophototrophs are known, some are yet to be identified or fully characterized in certain organisms. A recently characterized enzyme in oxygenic phototrophs is 15-cis-zeta(ζ)-carotene isomerase (Z-ISO), which catalyzes the cis-to-trans isomerization of the central 15–15′ cis double bond in 9,15,9′-tri-cis-ζ-carotene to produce 9,9′-di-cis-ζ-carotene during the four-step conversion of phytoene to lycopene. Z-ISO is a heme B-containing enzyme best studied in angiosperms. Homologs of Z-ISO are present in organisms that use the multi-enzyme poly-cis phytoene desaturation pathway, including algae and cyanobacteria, but appear to be absent in green bacteria. Here we confirm the identity of Z-ISO in the model unicellular cyanobacterium Synechocystis sp. PCC 6803 by showing that the protein encoded by the slr1599 open reading frame has ζ-carotene isomerase activity when produced in Escherichia coli. A Synechocystis Δslr1599 mutant synthesizes a normal quota of carotenoids when grown under illumination, where the photolabile 15–15′ cis double bond of 9,15,9′-tri-cis-ζ-carotene is isomerized by light, but accumulates this intermediate and fails to produce ‘mature’ carotenoid species during light-activated heterotrophic growth, demonstrating the requirement of Z-ISO for carotenoid biosynthesis during periods of darkness. In the absence of a structure of Z-ISO, we analyze AlphaFold models of the Synechocystis, Zea mays (maize), and Arabidopsis thaliana enzymes, identifying putative protein ligands for the heme B cofactor and the substrate-binding site.
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Affiliation(s)
- Matthew S. Proctor
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
| | | | - Daniel P. Canniffe
- Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK
| | | | - David J. K. Swainsbury
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | | | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - George A. Sutherland
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
| | - Andrew Hitchcock
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (M.S.P.); (G.A.S.); (A.H.)
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9
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Savinov A, Fernandez A, Fields S. Mapping functional regions of essential bacterial proteins with dominant-negative protein fragments. Proc Natl Acad Sci U S A 2022; 119:e2200124119. [PMID: 35749361 PMCID: PMC9245647 DOI: 10.1073/pnas.2200124119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/08/2022] [Indexed: 12/26/2022] Open
Abstract
Massively parallel measurements of dominant-negative inhibition by protein fragments have been used to map protein interaction sites and discover peptide inhibitors. However, the underlying principles governing fragment-based inhibition have thus far remained unclear. Here, we adapted a high-throughput inhibitory fragment assay for use in Escherichia coli, applying it to a set of 10 essential proteins. This approach yielded single amino acid resolution maps of inhibitory activity, with peaks localized to functionally important interaction sites, including oligomerization interfaces and folding contacts. Leveraging these data, we performed a systematic analysis to uncover principles of fragment-based inhibition. We determined a robust negative correlation between susceptibility to inhibition and cellular protein concentration, demonstrating that inhibitory fragments likely act primarily by titrating native protein interactions. We also characterized a series of trade-offs related to fragment length, showing that shorter peptides allow higher-resolution mapping but suffer from lower inhibitory activity. We employed an unsupervised statistical analysis to show that the inhibitory activities of protein fragments are largely driven not by generic properties such as charge, hydrophobicity, and secondary structure, but by the more specific characteristics of their bespoke macromolecular interactions. Overall, this work demonstrates fundamental characteristics of inhibitory protein fragment function and provides a foundation for understanding and controlling protein interactions in vivo.
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Affiliation(s)
- Andrew Savinov
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
| | - Andres Fernandez
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
| | - Stanley Fields
- Department of Genome Sciences, University of Washington, Seattle, WA 98195
- Department of Medicine, University of Washington, Seattle, WA 98195
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10
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Abstract
While most small, regulatory RNAs are thought to be “noncoding,” a few have been found to also encode a small protein. Here we describe a 164-nucleotide RNA that encodes a 28-amino acid, amphipathic protein, which interacts with aerobic glycerol-3-phosphate dehydrogenase and increases dehydrogenase activity but also base pairs with two mRNAs to reduce expression. The coding and base-pairing sequences overlap, and the two regulatory functions compete. Bacteria have evolved small RNAs (sRNAs) to regulate numerous biological processes and stress responses. While sRNAs generally are considered to be “noncoding,” a few have been found to also encode a small protein. Here we describe one such dual-function RNA that modulates carbon utilization in Escherichia coli. The 164-nucleotide RNA was previously shown to encode a 28-amino acid protein (denoted AzuC). We discovered the membrane-associated AzuC protein interacts with GlpD, the aerobic glycerol-3-phosphate dehydrogenase, and increases dehydrogenase activity. Overexpression of the RNA encoding AzuC results in a growth defect in glycerol and galactose medium. The defect in galactose medium was still observed for a stop codon mutant derivative, suggesting a second role for the RNA. Consistent with this observation, we found that cadA and galE are repressed by base pairing with the RNA (denoted AzuR). Interestingly, AzuC translation interferes with the observed repression of cadA and galE by the RNA and base pairing interferes with AzuC translation, demonstrating that the translation and base-pairing functions compete.
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Abstract
In recent years, there has been increased appreciation that a whole category of proteins, small proteins of around 50 amino acids or fewer in length, has been missed by annotation as well as by genetic and biochemical assays. With the increased recognition that small proteins are stable within cells and have regulatory functions, there has been intensified study of these proteins. As a result, important questions about small proteins in bacteria and archaea are coming to the fore. Here, we give an overview of these questions, the initial answers, and the approaches needed to address these questions more fully. More detailed discussions of how small proteins can be identified by ribosome profiling and mass spectrometry approaches are provided by two accompanying reviews (N. Vazquez-Laslop, C. M. Sharma, A. S. Mankin, and A. R. Buskirk, J Bacteriol 204:e00294-21, 2022, https://doi.org/10.1128/JB.00294-21; C. H. Ahrens, J. T. Wade, M. M. Champion, and J. D. Langer, J Bacteriol 204:e00353-21, 2022, https://doi.org/10.1128/JB.00353-21). We are excited by the prospects of new insights and possible therapeutic approaches coming from this emerging field.
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Affiliation(s)
- Todd Gray
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
| | - Kai Papenfort
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
- Microverse Cluster, Friedrich Schiller University, Jena, Germany
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12
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Yadavalli SS, Yuan J. Bacterial Small Membrane Proteins: the Swiss Army Knife of Regulators at the Lipid Bilayer. J Bacteriol 2022; 204:e0034421. [PMID: 34516282 PMCID: PMC8765417 DOI: 10.1128/jb.00344-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small membrane proteins represent a subset of recently discovered small proteins (≤100 amino acids), which are a ubiquitous class of emerging regulators underlying bacterial adaptation to environmental stressors. Until relatively recently, small open reading frames encoding these proteins were not designated genes in genome annotations. Therefore, our understanding of small protein biology was primarily limited to a few candidates associated with previously characterized larger partner proteins. Following the first systematic analyses of small proteins in Escherichia coli over a decade ago, numerous small proteins across different bacteria have been uncovered. An estimated one-third of these newly discovered proteins in E. coli are localized to the cell membrane, where they may interact with distinct groups of membrane proteins, such as signal receptors, transporters, and enzymes, and affect their activities. Recently, there has been considerable progress in functionally characterizing small membrane protein regulators aided by innovative tools adapted specifically to study small proteins. Our review covers prototypical proteins that modulate a broad range of cellular processes, such as transport, signal transduction, stress response, respiration, cell division, sporulation, and membrane stability. Thus, small membrane proteins represent a versatile group of physiology regulators at the membrane and the whole cell. Additionally, small membrane proteins have the potential for clinical applications, where some of the proteins may act as antibacterial agents themselves while others serve as alternative drug targets for the development of novel antimicrobials.
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Affiliation(s)
- Srujana S. Yadavalli
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey, USA
- Department of Genetics, Rutgers University, Piscataway, New Jersey, USA
| | - Jing Yuan
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
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13
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Takada K, Hama K, Sasaki T, Otsuka Y. The hokW-sokW Locus Encodes a Type I Toxin-Antitoxin System That Facilitates the Release of Lysogenic Sp5 Phage in Enterohemorrhagic Escherichia coli O157. Toxins (Basel) 2021; 13:toxins13110796. [PMID: 34822580 PMCID: PMC8621323 DOI: 10.3390/toxins13110796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
The toxin-antitoxin (TA) genetic modules control various bacterial events, such as plasmid maintenance, persister cell formation, and phage defense. They also exist in mobile genetic elements, including prophages; however, their physiological roles remain poorly understood. Here, we demonstrate that hokW-sokW, a putative TA locus encoded in Sakai prophage 5 (Sp5) in enterohemorrhagic Escherichia coli O157: H7 Sakai strain, functions as a type I TA system. Bacterial growth assays showed that the antitoxic activity of sokW RNA against HokW toxin partially requires an endoribonuclease, RNase III, and an RNA chaperone, Hfq. We also demonstrated that hokW-sokW assists Sp5-mediated lysis of E. coli cells when prophage induction is promoted by the DNA-damaging agent mitomycin C (MMC). We found that MMC treatment diminished sokW RNA and increased both the expression level and inner membrane localization of HokW in a RecA-dependent manner. Remarkably, the number of released Sp5 phages decreased by half in the absence of hokW-sokW. These results suggest that hokW-sokW plays a novel role as a TA system that facilitates the release of Sp5 phage progeny through E. coli lysis.
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14
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Fijalkowski I, Peeters MKR, Van Damme P. Small Protein Enrichment Improves Proteomics Detection of sORF Encoded Polypeptides. Front Genet 2021; 12:713400. [PMID: 34721520 PMCID: PMC8554064 DOI: 10.3389/fgene.2021.713400] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 10/01/2021] [Indexed: 11/13/2022] Open
Abstract
With the rapid growth in the number of sequenced genomes, genome annotation efforts became almost exclusively reliant on automated pipelines. Despite their unquestionable utility, these methods have been shown to underestimate the true complexity of the studied genomes, with small open reading frames (sORFs; ORFs typically considered shorter than 300 nucleotides) and, in consequence, their protein products (sORF encoded polypeptides or SEPs) being the primary example of a poorly annotated and highly underexplored class of genomic elements. With the advent of advanced translatomics such as ribosome profiling, reannotation efforts have progressed a great deal in providing translation evidence for numerous, previously unannotated sORFs. However, proteomics validation of these riboproteogenomics discoveries remains challenging due to their short length and often highly variable physiochemical properties. In this work we evaluate and compare tailored, yet easily adaptable, protein extraction methodologies for their efficacy in the extraction and concomitantly proteomics detection of SEPs expressed in the prokaryotic model pathogen Salmonella typhimurium (S. typhimurium). Further, an optimized protocol for the enrichment and efficient detection of SEPs making use of the of amphipathic polymer amphipol A8-35 and relying on differential peptide vs. protein solubility was developed and compared with global extraction methods making use of chaotropic agents. Given the versatile biological functions SEPs have been shown to exert, this work provides an accessible protocol for proteomics exploration of this fascinating class of small proteins.
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Affiliation(s)
- Igor Fijalkowski
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Gent, Belgium
| | - Marlies K. R. Peeters
- BioBix, Department of Data Analysis and Mathematical Modelling, Ghent University, Gent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Gent, Belgium
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15
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Abstract
Escherichia coli was one of the first species to have its genome sequenced and remains one of the best-characterized model organisms. Thus, it is perhaps surprising that recent studies have shown that a substantial number of genes have been overlooked. Genes encoding more than 140 small proteins, defined as those containing 50 or fewer amino acids, have been identified in E. coli in the past 10 years, and there is substantial evidence indicating that many more remain to be discovered. This review covers the methods that have been successful in identifying small proteins and the short open reading frames that encode them. The small proteins that have been functionally characterized to date in this model organism are also discussed. It is hoped that the review, along with the associated databases of known as well as predicted but undetected small proteins, will aid in and provide a roadmap for the continued identification and characterization of these proteins in E. coli as well as other bacteria.
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16
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Membrane Insertion of the M13 Minor Coat Protein G3p Is Dependent on YidC and the SecAYEG Translocase. Viruses 2021; 13:v13071414. [PMID: 34372619 PMCID: PMC8310372 DOI: 10.3390/v13071414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 01/01/2023] Open
Abstract
The minor coat protein G3p of bacteriophage M13 is the key component for the host interaction of this virus and binds to Escherichia coli at the tip of the F pili. As we show here, during the biosynthesis of G3p as a preprotein, the signal sequence interacts primarily with SecY, whereas the hydrophobic anchor sequence at the C-terminus interacts with YidC. Using arrested nascent chains and thiol crosslinking, we show here that the ribosome-exposed signal sequence is first contacted by SecY but not by YidC, suggesting that only SecYEG is involved at this early stage. The protein has a large periplasmic domain, a hydrophobic anchor sequence of 21 residues and a short C-terminal tail that remains in the cytoplasm. During the later synthesis of the entire G3p, the residues 387, 389 and 392 in anchor domain contact YidC in its hydrophobic slide to hold translocation of the C-terminal tail. Finally, the protein is processed by leader peptidase and assembled into new progeny phage particles that are extruded out of the cell.
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17
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Fuchs S, Kucklick M, Lehmann E, Beckmann A, Wilkens M, Kolte B, Mustafayeva A, Ludwig T, Diwo M, Wissing J, Jänsch L, Ahrens CH, Ignatova Z, Engelmann S. Towards the characterization of the hidden world of small proteins in Staphylococcus aureus, a proteogenomics approach. PLoS Genet 2021; 17:e1009585. [PMID: 34061833 PMCID: PMC8195425 DOI: 10.1371/journal.pgen.1009585] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 06/11/2021] [Accepted: 05/07/2021] [Indexed: 01/08/2023] Open
Abstract
Small proteins play essential roles in bacterial physiology and virulence, however, automated algorithms for genome annotation are often not yet able to accurately predict the corresponding genes. The accuracy and reliability of genome annotations, particularly for small open reading frames (sORFs), can be significantly improved by integrating protein evidence from experimental approaches. Here we present a highly optimized and flexible bioinformatics workflow for bacterial proteogenomics covering all steps from (i) generation of protein databases, (ii) database searches and (iii) peptide-to-genome mapping to (iv) visualization of results. We used the workflow to identify high quality peptide spectrum matches (PSMs) for small proteins (≤ 100 aa, SP100) in Staphylococcus aureus Newman. Protein extracts from S. aureus were subjected to different experimental workflows for protein digestion and prefractionation and measured with highly sensitive mass spectrometers. In total, 175 proteins with up to 100 aa (SP100) were identified. Out of these 24 (ranging from 9 to 99 aa) were novel and not contained in the used genome annotation.144 SP100 are highly conserved and were found in at least 50% of the publicly available S. aureus genomes, while 127 are additionally conserved in other staphylococci. Almost half of the identified SP100 were basic, suggesting a role in binding to more acidic molecules such as nucleic acids or phospholipids.
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Affiliation(s)
- Stephan Fuchs
- Robert Koch Institute, Methodenentwicklung und Forschungsinfrastruktur (MF), Berlin, Germany
| | - Martin Kucklick
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Erik Lehmann
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Alexander Beckmann
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Maya Wilkens
- Robert Koch Institute, Methodenentwicklung und Forschungsinfrastruktur (MF), Berlin, Germany
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Baban Kolte
- University of Hamburg, Institute of Biochemistry and Molecular Biology, Hamburg, Germany
| | - Ayten Mustafayeva
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Tobias Ludwig
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Maurice Diwo
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
| | - Josef Wissing
- Helmholtz Center for Infection Research GmbH, Cellular Proteomics, Braunschweig, Germany
| | - Lothar Jänsch
- Helmholtz Center for Infection Research GmbH, Cellular Proteomics, Braunschweig, Germany
| | - Christian H Ahrens
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Zoya Ignatova
- University of Hamburg, Institute of Biochemistry and Molecular Biology, Hamburg, Germany
| | - Susanne Engelmann
- University of Technical Sciences Braunschweig, Institute for Microbiology, Braunschweig, Germany
- Helmholtz Center for Infection Research GmbH, Microbial Proteomics, Braunschweig, Germany
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18
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Steinberg R, Koch HG. The largely unexplored biology of small proteins in pro- and eukaryotes. FEBS J 2021; 288:7002-7024. [PMID: 33780127 DOI: 10.1111/febs.15845] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/29/2022]
Abstract
The large abundance of small open reading frames (smORFs) in prokaryotic and eukaryotic genomes and the plethora of smORF-encoded small proteins became only apparent with the constant advancements in bioinformatic, genomic, proteomic, and biochemical tools. Small proteins are typically defined as proteins of < 50 amino acids in prokaryotes and of less than 100 amino acids in eukaryotes, and their importance for cell physiology and cellular adaptation is only beginning to emerge. In contrast to antimicrobial peptides, which are secreted by prokaryotic and eukaryotic cells for combatting pathogens and competitors, small proteins act within the producing cell mainly by stabilizing protein assemblies and by modifying the activity of larger proteins. Production of small proteins is frequently linked to stress conditions or environmental changes, and therefore, cells seem to use small proteins as intracellular modifiers for adjusting cell metabolism to different intra- and extracellular cues. However, the size of small proteins imposes a major challenge for the cellular machinery required for protein folding and intracellular trafficking and recent data indicate that small proteins can engage distinct trafficking pathways. In the current review, we describe the diversity of small proteins in prokaryotes and eukaryotes, highlight distinct and common features, and illustrate how they are handled by the protein trafficking machineries in prokaryotic and eukaryotic cells. Finally, we also discuss future topics of research on this fascinating but largely unexplored group of proteins.
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Affiliation(s)
- Ruth Steinberg
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
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19
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Fijalkowska D, Fijalkowski I, Willems P, Van Damme P. Bacterial riboproteogenomics: the era of N-terminal proteoform existence revealed. FEMS Microbiol Rev 2021; 44:418-431. [PMID: 32386204 DOI: 10.1093/femsre/fuaa013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/07/2020] [Indexed: 12/17/2022] Open
Abstract
With the rapid increase in the number of sequenced prokaryotic genomes, relying on automated gene annotation became a necessity. Multiple lines of evidence, however, suggest that current bacterial genome annotations may contain inconsistencies and are incomplete, even for so-called well-annotated genomes. We here discuss underexplored sources of protein diversity and new methodologies for high-throughput genome reannotation. The expression of multiple molecular forms of proteins (proteoforms) from a single gene, particularly driven by alternative translation initiation, is gaining interest as a prominent contributor to bacterial protein diversity. In consequence, riboproteogenomic pipelines were proposed to comprehensively capture proteoform expression in prokaryotes by the complementary use of (positional) proteomics and the direct readout of translated genomic regions using ribosome profiling. To complement these discoveries, tailored strategies are required for the functional characterization of newly discovered bacterial proteoforms.
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Affiliation(s)
- Daria Fijalkowska
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Igor Fijalkowski
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Patrick Willems
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Petra Van Damme
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
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20
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Bogati B, Wadsworth N, Barrera F, Fozo EM. Improved growth of Escherichia coli in aminoglycoside antibiotics by the zor-orz toxin-antitoxin system. J Bacteriol 2021; 204:JB0040721. [PMID: 34570627 PMCID: PMC8765423 DOI: 10.1128/jb.00407-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/21/2021] [Indexed: 11/20/2022] Open
Abstract
Type I toxin-antitoxin systems consist of a small protein (under 60 amino acids) whose overproduction can result in cell growth stasis or death, and a small RNA that represses translation of the toxin mRNA. Despite their potential toxicity, type I toxin proteins are increasingly linked to improved survival of bacteria in stressful environments and antibiotic persistence. While the interaction of toxin mRNAs with their cognate antitoxin sRNAs in some systems are well characterized, additional translational control of many toxins and their biological roles are not well understood. Using an ectopic overexpression system, we show that the efficient translation of a chromosomally encoded type I toxin, ZorO, requires mRNA processing of its long 5' untranslated region (UTR; Δ28 UTR). The severity of ZorO induced toxicity on growth inhibition, membrane depolarization, and ATP depletion were significantly increased if expressed from the Δ28 UTR versus the full-length UTR. ZorO did not form large pores as evident via a liposomal leakage assay, in vivo morphological analyses, and measurement of ATP loss. Further, increasing the copy number of the entire zor-orz locus significantly improved growth of bacterial cells in the presence of kanamycin and increased the minimum inhibitory concentration against kanamycin and gentamycin; however, no such benefit was observed against other antibiotics. This supports a role for the zor-orz locus as a protective measure against specific stress agents and is likely not part of a general stress response mechanism. Combined, these data shed more insights into the possible native functions for type I toxin proteins. IMPORTANCE Bacterial species can harbor gene pairs known as type I toxin-antitoxin systems where one gene encodes a small protein that is toxic to the bacteria producing it and a second gene that encodes a small RNA antitoxin to prevent toxicity. While artificial overproduction of type I toxin proteins can lead to cell growth inhibition and cell lysis, the endogenous translation of type I toxins appears to be tightly regulated. Here, we show translational regulation controls production of the ZorO type I toxin and prevents subsequent negative effects on the cell. Further, we demonstrate a role for zorO and its cognate antitoxin in improved growth of E. coli in the presence of aminoglycoside antibiotics.
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Affiliation(s)
- Bikash Bogati
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Nicholas Wadsworth
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Francisco Barrera
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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21
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Hariharan B, Pross E, Soman R, Kaushik S, Kuhn A, Dalbey RE. Polarity/charge as a determinant of translocase requirements for membrane protein insertion. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183502. [PMID: 33130098 DOI: 10.1016/j.bbamem.2020.183502] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/12/2020] [Accepted: 10/21/2020] [Indexed: 11/17/2022]
Abstract
The YidC insertase of Escherichia coli inserts membrane proteins with small periplasmic loops (~20 residues). However, it has difficulty transporting loops that contain positively charged residues compared to negatively charged residues and, as a result, increasing the positive charge has an increased requirement for the Sec machinery as compared to negatively charged loops (Zhu et al., 2013; Soman et al., 2014). This suggested that the polarity and charge of the periplasmic regions of membrane proteins determine the YidC and Sec translocase requirements for insertion. Here we tested this polarity/charge hypothesis by showing that insertion of our model substrate protein procoat-Lep can become YidC/Sec dependent when the periplasmic loop was converted to highly polar even in the absence of any charged residues. Moreover, adding a number of hydrophobic amino acids to a highly polar loop can decrease the Sec-dependence of the otherwise strictly Sec-dependent membrane proteins. We also demonstrate that the length of the procoat-Lep loop is indeed a determinant for Sec-dependence by inserting alanine residues that do not markedly change the overall hydrophilicity of the periplasmic loop. Taken together, the results support the polarity/charge hypothesis as a determinant for the translocase requirement for procoat insertion.
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Affiliation(s)
- Balasubramani Hariharan
- Dept. of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States of America
| | - Eva Pross
- Institute of Biology, University of Hohenheim, Stuttgart 70599, Germany
| | - Raunak Soman
- Dept. of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States of America
| | - Sharbani Kaushik
- Dept. of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States of America
| | - Andreas Kuhn
- Institute of Biology, University of Hohenheim, Stuttgart 70599, Germany
| | - Ross E Dalbey
- Dept. of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States of America.
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22
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Steinberg R, Origi A, Natriashvili A, Sarmah P, Licheva M, Walker PM, Kraft C, High S, Luirink J, Shi WQ, Helmstädter M, Ulbrich MH, Koch HG. Posttranslational insertion of small membrane proteins by the bacterial signal recognition particle. PLoS Biol 2020; 18:e3000874. [PMID: 32997663 PMCID: PMC7549839 DOI: 10.1371/journal.pbio.3000874] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 10/12/2020] [Accepted: 09/02/2020] [Indexed: 01/05/2023] Open
Abstract
Small membrane proteins represent a largely unexplored yet abundant class of proteins in pro- and eukaryotes. They essentially consist of a single transmembrane domain and are associated with stress response mechanisms in bacteria. How these proteins are inserted into the bacterial membrane is unknown. Our study revealed that in Escherichia coli, the 27-amino-acid-long model protein YohP is recognized by the signal recognition particle (SRP), as indicated by in vivo and in vitro site-directed cross-linking. Cross-links to SRP were also observed for a second small membrane protein, the 33-amino-acid-long YkgR. However, in contrast to the canonical cotranslational recognition by SRP, SRP was found to bind to YohP posttranslationally. In vitro protein transport assays in the presence of a SecY inhibitor and proteoliposome studies demonstrated that SRP and its receptor FtsY are essential for the posttranslational membrane insertion of YohP by either the SecYEG translocon or by the YidC insertase. Furthermore, our data showed that the yohP mRNA localized preferentially and translation-independently to the bacterial membrane in vivo. In summary, our data revealed that YohP engages an unique SRP-dependent posttranslational insertion pathway that is likely preceded by an mRNA targeting step. This further highlights the enormous plasticity of bacterial protein transport machineries. Small membrane proteins represent a largely unexplored yet abundant class of proteins, but how they are inserted into the bacterial membrane is unknown. This study identifies a novel posttranslational protein transport pathway that relies on the signal recognition particle and the SecYEG translocon/YidC insertase.
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Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Princess M. Walker
- Department of Chemistry, Ball State University, Muncie, Indiana, United States of America
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Stephen High
- School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Joen Luirink
- Molecular Microbiology, AIMMS, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Wei. Q. Shi
- Department of Chemistry, Ball State University, Muncie, Indiana, United States of America
| | - Martin Helmstädter
- Internal Medicine IV, Department of Medicine, Medical Center − University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian H. Ulbrich
- Internal Medicine IV, Department of Medicine, Medical Center − University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- * E-mail:
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23
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Strategies for Optimizing the Production of Proteins and Peptides with Multiple Disulfide Bonds. Antibiotics (Basel) 2020; 9:antibiotics9090541. [PMID: 32858882 PMCID: PMC7558204 DOI: 10.3390/antibiotics9090541] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 02/07/2023] Open
Abstract
Bacteria can produce recombinant proteins quickly and cost effectively. However, their physiological properties limit their use for the production of proteins in their native form, especially polypeptides that are subjected to major post-translational modifications. Proteins that rely on disulfide bridges for their stability are difficult to produce in Escherichia coli. The bacterium offers the least costly, simplest, and fastest method for protein production. However, it is difficult to produce proteins with a very large size. Saccharomyces cerevisiae and Pichia pastoris are the most commonly used yeast species for protein production. At a low expense, yeasts can offer high protein yields, generate proteins with a molecular weight greater than 50 kDa, extract signal sequences, and glycosylate proteins. Both eukaryotic and prokaryotic species maintain reducing conditions in the cytoplasm. Hence, the formation of disulfide bonds is inhibited. These bonds are formed in eukaryotic cells during the export cycle, under the oxidizing conditions of the endoplasmic reticulum. Bacteria do not have an advanced subcellular space, but in the oxidizing periplasm, they exhibit both export systems and enzymatic activities directed at the formation and quality of disulfide bonds. Here, we discuss current techniques used to target eukaryotic and prokaryotic species for the generation of correctly folded proteins with disulfide bonds.
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Garai P, Blanc‐Potard A. Uncovering small membrane proteins in pathogenic bacteria: Regulatory functions and therapeutic potential. Mol Microbiol 2020; 114:710-720. [DOI: 10.1111/mmi.14564] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 01/01/2023]
Affiliation(s)
- Preeti Garai
- Laboratory of Pathogen‐Host Interactions Université de MontpellierCNRS‐UMR5235 Montpellier France
| | - Anne Blanc‐Potard
- Laboratory of Pathogen‐Host Interactions Université de MontpellierCNRS‐UMR5235 Montpellier France
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Homologous bd oxidases share the same architecture but differ in mechanism. Nat Commun 2019; 10:5138. [PMID: 31723136 PMCID: PMC6853902 DOI: 10.1038/s41467-019-13122-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/22/2019] [Indexed: 11/25/2022] Open
Abstract
Cytochrome bd oxidases are terminal reductases of bacterial and archaeal respiratory chains. The enzyme couples the oxidation of ubiquinol or menaquinol with the reduction of dioxygen to water, thus contributing to the generation of the protonmotive force. Here, we determine the structure of the Escherichia coli bd oxidase treated with the specific inhibitor aurachin by cryo-electron microscopy (cryo-EM). The major subunits CydA and CydB are related by a pseudo two fold symmetry. The heme b and d cofactors are found in CydA, while ubiquinone-8 is bound at the homologous positions in CydB to stabilize its structure. The architecture of the E. coli enzyme is highly similar to that of Geobacillus thermodenitrificans, however, the positions of heme b595 and d are interchanged, and a common oxygen channel is blocked by a fourth subunit and substituted by a more narrow, alternative channel. Thus, with the same overall fold, the homologous enzymes exhibit a different mechanism. Cytochrome bd oxidases couple quinol oxidation and the release of protons to the periplasmic side with proton uptake from the cytoplasmic side to reduce dioxygen to water and they are the terminal reductases in bacterial and archaeal respiratory chains. Here the authors present the cryo-EM structure of Escherichia coli bd oxidase and discuss mechanistic implications.
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Steinberg R, Knüpffer L, Origi A, Asti R, Koch HG. Co-translational protein targeting in bacteria. FEMS Microbiol Lett 2019; 365:4966980. [PMID: 29790984 DOI: 10.1093/femsle/fny095] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/09/2018] [Indexed: 01/16/2023] Open
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and have to be transported into or across the cytoplasmic membrane. Bacteria use multiple protein transport systems in parallel, but the majority of proteins engage two distinct targeting systems. One is the co-translational targeting by two universally conserved GTPases, the signal recognition particle (SRP) and its receptor FtsY, which deliver inner membrane proteins to either the SecYEG translocon or the YidC insertase for membrane insertion. The other targeting system depends on the ATPase SecA, which targets secretory proteins, i.e. periplasmic and outer membrane proteins, to SecYEG for their subsequent ATP-dependent translocation. While SRP selects its substrates already very early during their synthesis, the recognition of secretory proteins by SecA is believed to occur primarily after translation termination, i.e. post-translationally. In this review we highlight recent progress on how SRP recognizes its substrates at the ribosome and how the fidelity of the targeting reaction to SecYEG is maintained. We furthermore discuss similarities and differences in the SRP-dependent targeting to either SecYEG or YidC and summarize recent results that suggest that some membrane proteins are co-translationally targeted by SecA.
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Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Lara Knüpffer
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, Freiburg D-79104, Germany
| | - Rossella Asti
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
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A Short Peptide Derived from the ZorO Toxin Functions as an Effective Antimicrobial. Toxins (Basel) 2019; 11:toxins11070392. [PMID: 31277504 PMCID: PMC6669753 DOI: 10.3390/toxins11070392] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/28/2019] [Accepted: 06/30/2019] [Indexed: 11/21/2022] Open
Abstract
Antimicrobial peptides are potential molecules for the development of novel antibiotic agents. The ZorO toxin of a type I toxin–antitoxin system in Escherichia coli O157:H7 is composed of 29 amino acids and its endogenous expression inhibits E. coli growth. However, little is known about its inhibitory mechanism. In this study, we demonstrate that the ZorO localized in the inner membrane affects the plasma membrane integrity and potential when expressed in E. coli cells, which triggers the production of cytotoxic hydroxyl radicals. We further show that five internal amino acids (Ala–Leu–Leu–Arg–Leu; ALLRL) of ZorO are necessary for its toxicity. This result prompted us to address the potential of the synthetic ALLRL peptide as an antimicrobial. Exogenously-added ALLRL peptide to Gram-positive bacteria, Staphylococcus aureus and Bacillus subtilis, and a fungus, Candida albicans, trigger cell membrane damage and exhibit growth defect, while having no effect on Gram-negative bacterium, E. coli. The ALLRL peptide retains its activity under the physiological salt concentrations, which is in contrast to natural antimicrobial peptides. Importantly, this peptide has no toxicity against mammalian cells. Taken together, an effective and short peptide, ALLRL, would be an attractive antimicrobial to Gram-positive bacteria and C. albicans.
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Abstract
Diverse mechanisms and functions of posttranscriptional regulation by small regulatory RNAs and RNA-binding proteins have been described in bacteria. In contrast, little is known about the spatial organization of RNAs in bacterial cells. In eukaryotes, subcellular localization and transport of RNAs play important roles in diverse physiological processes, such as embryonic patterning, asymmetric cell division, epithelial polarity, and neuronal plasticity. It is now clear that bacterial RNAs also can accumulate at distinct sites in the cell. However, due to the small size of bacterial cells, RNA localization and localization-associated functions are more challenging to study in bacterial cells, and the underlying molecular mechanisms of transcript localization are less understood. Here, we review the emerging examples of RNAs localized to specific subcellular locations in bacteria, with indications that subcellular localization of transcripts might be important for gene expression and regulatory processes. Diverse mechanisms for bacterial RNA localization have been suggested, including close association to their genomic site of transcription, or to the localizations of their protein products in translation-dependent or -independent processes. We also provide an overview of the state of the art of technologies to visualize and track bacterial RNAs, ranging from hybridization-based approaches in fixed cells to in vivo imaging approaches using fluorescent protein reporters and/or RNA aptamers in single living bacterial cells. We conclude with a discussion of open questions in the field and ongoing technological developments regarding RNA imaging in eukaryotic systems that might likewise provide novel insights into RNA localization in bacteria.
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Abstract
Bacterial populations harbor a small fraction of cells that display transient multidrug tolerance. These so-called persister cells are extremely difficult to eradicate and contribute to the recalcitrance of chronic infections. Several signaling pathways leading to persistence have been identified. However, it is poorly understood how the effectors of these pathways function at the molecular level. In a previous study, we reported that the conserved GTPase Obg induces persistence in Escherichia coli via transcriptional upregulation of the toxin HokB. In the present study, we demonstrate that HokB inserts in the cytoplasmic membrane where it forms pores. The pore-forming capacity of the HokB peptide is demonstrated by in vitro conductance measurements on synthetic and natural lipid bilayers, revealing an asymmetrical conductance profile. Pore formation is directly linked to persistence and results in leakage of intracellular ATP. HokB-induced persistence is strongly impeded in the presence of a channel blocker, thereby providing a direct link between pore functioning and persistence. Furthermore, the activity of HokB pores is sensitive to the membrane potential. This sensitivity presumably results from the formation of either intermediate or mature pore types depending on the membrane potential. Taken together, these results provide a detailed view on the mechanistic basis of persister formation through the effector HokB.IMPORTANCE There is increasing awareness of the clinical importance of persistence. Indeed, persistence is linked to the recalcitrance of chronic infections, and evidence is accumulating that persister cells constitute a pool of viable cells from which resistant mutants can emerge. Unfortunately, persistence is a poorly understood process at the mechanistic level. In this study, we unraveled the pore-forming activity of HokB in E. coli and discovered that these pores lead to leakage of intracellular ATP, which is correlated with the induction of persistence. Moreover, we established a link between persistence and pore activity, as the number of HokB-induced persister cells was strongly reduced using a channel blocker. The latter opens opportunities to reduce the number of persister cells in a clinical setting.
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Peschke M, Le Goff M, Koningstein GM, Karyolaimos A, de Gier JW, van Ulsen P, Luirink J. SRP, FtsY, DnaK and YidC Are Required for the Biogenesis of the E. coli Tail-Anchored Membrane Proteins DjlC and Flk. J Mol Biol 2017; 430:389-403. [PMID: 29246766 DOI: 10.1016/j.jmb.2017.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/19/2022]
Abstract
Tail-anchored membrane proteins (TAMPs) are relatively simple membrane proteins characterized by a single transmembrane domain (TMD) at their C-terminus. Consequently, the hydrophobic TMD, which acts as a subcellular targeting signal, emerges from the ribosome only after termination of translation precluding canonical co-translational targeting and membrane insertion. In contrast to the well-studied eukaryotic TAMPs, surprisingly little is known about the cellular components that facilitate the biogenesis of bacterial TAMPs. In this study, we identify DjlC and Flk as bona fide Escherichia coli TAMPs and show that their TMDs are necessary and sufficient for authentic membrane targeting of the fluorescent reporter mNeonGreen. Using strains conditional for the expression of known E. coli membrane targeting and insertion factors, we demonstrate that the signal recognition particle (SRP), its receptor FtsY, the chaperone DnaK and insertase YidC are each required for efficient membrane localization of both TAMPs. A close association between the TMD of DjlC and Flk with both the Ffh subunit of SRP and YidC was confirmed by site-directed in vivo photo-crosslinking. In addition, our data suggest that the hydrophobicity of the TMD correlates with the dependency on SRP for efficient targeting.
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Affiliation(s)
- Markus Peschke
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Mélanie Le Goff
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Gregory M Koningstein
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Alexandros Karyolaimos
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Svante Arrhenius väg 16C, SE-106 91 Stockholm, Sweden
| | - Jan-Willem de Gier
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Svante Arrhenius väg 16C, SE-106 91 Stockholm, Sweden
| | - Peter van Ulsen
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Joen Luirink
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands.
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Cytoplasmic Localization of Sulfide:Quinone Oxidoreductase and Persulfide Dioxygenase of Cupriavidus pinatubonensis JMP134. Appl Environ Microbiol 2017; 83:AEM.01820-17. [PMID: 28939597 DOI: 10.1128/aem.01820-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 09/13/2017] [Indexed: 12/11/2022] Open
Abstract
Heterotrophic bacteria have recently been reported to oxidize sulfide to sulfite and thiosulfate by using sulfide:quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO). In chemolithotrophic bacteria, both SQR and PDO have been reported to function in the periplasmic space, with SQR as a peripheral membrane protein whose C terminus inserts into the cytoplasmic membrane and PDO as a soluble protein. Cupriavidus pinatubonensis JMP134, best known for its ability to degrade 2,4-dichlorophenoxyacetic acid and other aromatic pollutants, has a gene cluster of sqr and pdo encoding C. pinatubonensis SQR (CpSQR) and CpPDO2. When cloned in Escherichia coli, the enzymes are functional. Here we investigated whether they function in the periplasmic space or in the cytoplasm in heterotrophic bacteria. By using sequence analysis, biochemical detection, and green fluorescent protein (GFP)/PhoA fusion proteins, we found that CpSQR was located on the cytoplasmic side of the membrane and CpPDO2 was a soluble protein in the cytoplasm with a tendency to be peripherally located near the membrane. The location proximity of these proteins near the membrane in the cytoplasm may facilitate sulfide oxidation in heterotrophic bacteria. The information may guide the use of heterotrophic bacteria in bioremediation of organic pollutants as well as H2S.IMPORTANCE Sulfide (H2S, HS-, and S2-), which is common in natural gas and wastewater, causes a serious malodor at low levels and is deadly at high levels. Microbial oxidation of sulfide is a valid bioremediation method, in which chemolithotrophic bacteria that use sulfide as the energy source are often used to remove sulfide. Heterotrophic bacteria with SQR and PDO have recently been reported to oxidize sulfide to sulfite and thiosulfate. Cupriavidus pinatubonensis JMP134 has been extensively characterized for its ability to degrade organic pollutants, and it also contains SQR and PDO. This paper shows the localization of SQR and PDO inside the cytoplasm in the vicinity of the membrane. The information may provide guidance for using heterotrophic bacteria in sulfide bioremediation.
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Okrent RA, Trippe KM, Maselko M, Manning V. Functional analysis of a biosynthetic cluster essential for production of 4-formylaminooxyvinylglycine, a germination-arrest factor from Pseudomonas fluorescens WH6. MICROBIOLOGY-SGM 2017; 163:207-217. [PMID: 28270265 DOI: 10.1099/mic.0.000418] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rhizosphere-associated Pseudomonas fluorescens WH6 produces the germination-arrest factor 4-formylaminooxyvinylglycine (FVG). FVG has previously been shown to both arrest the germination of weedy grasses and inhibit the growth of the bacterial plant pathogen Erwinia amylovora. Very little is known about the mechanism by which FVG is produced. Although a previous study identified a region of the genome that may be involved in FVG biosynthesis, it has not yet been determined which genes within that region are sufficient and necessary for FVG production. In the current study, we explored the role of each of the putative genes encoded in that region by constructing deletion mutations. Mutant strains were assayed for their ability to produce FVG with a combination of biological assays and TLC analyses. This work defined the core FVG biosynthetic gene cluster and revealed several interesting characteristics of FVG production. We determined that FVG biosynthesis requires two small ORFs of less than 150 nucleotides and that multiple transporters have overlapping but distinct functionality. In addition, two genes in the centre of the biosynthetic gene cluster are not required for FVG production, suggesting that additional products may be produced from the cluster. Transcriptional analysis indicated that at least three active promoters play a role in the expression of genes within this cluster. The results of this study enrich our knowledge regarding the diversity of mechanisms by which bacteria produce non-proteinogenic amino acids like vinylglycines.
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Affiliation(s)
- Rachel A Okrent
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.,USDA-ARS Forage Seed and Cereal Research Unit, Corvallis, OR, USA
| | - Kristin M Trippe
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR, USA.,USDA-ARS Forage Seed and Cereal Research Unit, Corvallis, OR, USA
| | - Maciej Maselko
- Present address: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, MN, USA.,USDA-ARS Forage Seed and Cereal Research Unit, Corvallis, OR, USA
| | - Viola Manning
- USDA-ARS Forage Seed and Cereal Research Unit, Corvallis, OR, USA
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Cortés M, Sánchez P, Ruiz P, Haro R, Sáez J, Sánchez F, Hernández M, Oliver C, Yáñez AJ. In vitro expression of Sec-dependent pathway and type 4B secretion system in Piscirickettsia salmonis. Microb Pathog 2017; 110:586-593. [PMID: 28789875 DOI: 10.1016/j.micpath.2017.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/18/2017] [Accepted: 08/04/2017] [Indexed: 11/18/2022]
Abstract
Piscirickettsia salmonis is an intracellular bacterium and the causative agent of Piscirickettsiosis, a disease responsible for considerable mortalities in the Chilean salmon farming industry. Currently, P. salmonis protein translocation across the membrane and the mechanisms by which virulence factors are delivered to host cells are poorly understood. However, it is known that Gram-negative bacteria possess several mechanisms that transport proteins to the periplasmic and extracellular compartments. The aim of this study was to evaluate the expressional changes of several genes in the P. salmonis Sec-dependent pathway and type 4B secretion system during in vitro infection. Genes homologous and the main proteins belonging to Sec-dependent pathway and Type 4 Dot/Icm secretion system were found in the genome and proteome of P. salmonis AUSTRAL-005 strain. Additionally, several genes of these protein transport mechanisms were overexpressed during in vitro P. salmonis infection in SHK-1 cell line. The obtained data indicate that the Sec-dependent pathway and Type 4B secretion system are biologically active during P. salmonis infection. These mechanisms could contribute to the recycling of proteins into the inner and outer bacterial membrane and in translocate virulence factors to infected cell, which would favor the structural integrity and virulence of this bacterium.
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Affiliation(s)
- Marcos Cortés
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile
| | - Patricio Sánchez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile
| | - Pamela Ruiz
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile
| | - Ronie Haro
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Austral-OMICS, Universidad Austral de Chile, 5110566 Valdivia, Chile
| | - Jerson Sáez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile
| | - Fabián Sánchez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile
| | - Mauricio Hernández
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Austral-OMICS, Universidad Austral de Chile, 5110566 Valdivia, Chile
| | - Cristian Oliver
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Universidad Andrés Bello, Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Viña del Mar, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile.
| | - Alejandro J Yáñez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, 5110566 Valdivia, Chile; Austral-OMICS, Universidad Austral de Chile, 5110566 Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), 4070007 Concepción, Chile.
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Lago M, Monteil V, Douche T, Guglielmini J, Criscuolo A, Maufrais C, Matondo M, Norel F. Proteome remodelling by the stress sigma factor RpoS/σ S in Salmonella: identification of small proteins and evidence for post-transcriptional regulation. Sci Rep 2017; 7:2127. [PMID: 28522802 PMCID: PMC5437024 DOI: 10.1038/s41598-017-02362-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/10/2017] [Indexed: 12/17/2022] Open
Abstract
The RpoS/σS sigma subunit of RNA polymerase is the master regulator of the general stress response in many Gram-negative bacteria. Extensive studies have been conducted on σS-regulated gene expression at the transcriptional level. In contrast, very limited information regarding the impact of σS on global protein production is available. In this study, we used a mass spectrometry-based proteomics approach to explore the wide σS-dependent proteome of the human pathogen Salmonella enterica serovar Typhimurium. Our present goals were twofold: (1) to survey the protein changes associated with the ΔrpoS mutation and (2) to assess the coding capacity of σS-dependent small RNAs. Our proteomics data, and complementary assays, unravelled the large impact of σS on the Salmonella proteome, and validated expression and σS regulation of twenty uncharacterized small proteins of 27 to 96 amino acids. Furthermore, a large number of genes regulated at the protein level only were identified, suggesting that post-transcriptional regulation is an important component of the σS response. Novel aspects of σS in the control of important catabolic pathways such as myo-inositol, L-fucose, propanediol, and ethanolamine were illuminated by this work, providing new insights into the physiological remodelling involved in bacterial adaptation to a non-actively growing state.
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Affiliation(s)
- Magali Lago
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Dr. Roux, 75015, Paris, France
- CNRS ERL6002, rue du Docteur Roux, 75015, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris, rue du Dr. Roux, 75015, Paris, France
| | - Véronique Monteil
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Dr. Roux, 75015, Paris, France
- CNRS ERL6002, rue du Docteur Roux, 75015, Paris, France
- Institut Pasteur, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie structurale et Chimie, rue du Dr. Roux, 75015, Paris, France
| | - Thibaut Douche
- Institut Pasteur, Unité de Spectrométrie de Masse Structurale et Protéomique, Département de Biologie Structurale et Chimie, UMR3528, rue du Dr. Roux, 75015, Paris, France
| | - Julien Guglielmini
- Institut Pasteur, Bioinformatics and Biostatistics Hub, C3BI, USR 3756 IP CNRS, rue du Dr. Roux, 75015, Paris, France
| | - Alexis Criscuolo
- Institut Pasteur, Bioinformatics and Biostatistics Hub, C3BI, USR 3756 IP CNRS, rue du Dr. Roux, 75015, Paris, France
| | - Corinne Maufrais
- Institut Pasteur, Bioinformatics and Biostatistics Hub, C3BI, USR 3756 IP CNRS, rue du Dr. Roux, 75015, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Unité de Spectrométrie de Masse Structurale et Protéomique, Département de Biologie Structurale et Chimie, UMR3528, rue du Dr. Roux, 75015, Paris, France
| | - Françoise Norel
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Dr. Roux, 75015, Paris, France.
- CNRS ERL6002, rue du Docteur Roux, 75015, Paris, France.
- Institut Pasteur, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie structurale et Chimie, rue du Dr. Roux, 75015, Paris, France.
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Increasing intracellular magnesium levels with the 31-amino acid MgtS protein. Proc Natl Acad Sci U S A 2017; 114:5689-5694. [PMID: 28512220 DOI: 10.1073/pnas.1703415114] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synthesis of the 31-amino acid, inner membrane protein MgtS (formerly denoted YneM) is induced by very low Mg2+ in a PhoPQ-dependent manner in Escherichia coli Here we report that MgtS acts to increase intracellular Mg2+ levels and maintain cell integrity upon Mg2+ depletion. Upon development of a functional tagged derivative of MgtS, we found that MgtS interacts with MgtA to increase the levels of this P-type ATPase Mg2+ transporter under Mg2+-limiting conditions. Correspondingly, the effects of MgtS upon Mg2+ limitation are lost in a ∆mgtA mutant, and MgtA overexpression can suppress the ∆mgtS phenotype. MgtS stabilization of MgtA provides an additional layer of regulation of this tightly controlled Mg2+ transporter and adds to the list of small proteins that regulate inner membrane transporters.
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Tail-Anchored Inner Membrane Protein ElaB Increases Resistance to Stress While Reducing Persistence in Escherichia coli. J Bacteriol 2017; 199:JB.00057-17. [PMID: 28242719 DOI: 10.1128/jb.00057-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 02/16/2017] [Indexed: 11/20/2022] Open
Abstract
Host-associated bacteria, such as Escherichia coli, often encounter various host-related stresses, such as nutritional deprivation, oxidative stress, and temperature shifts. There is growing interest in searching for small endogenous proteins that mediate stress responses. Here, we characterized the small C-tail-anchored inner membrane protein ElaB in E. coli ElaB belongs to a class of tail-anchored inner membrane proteins with a C-terminal transmembrane domain but lacking an N-terminal signal sequence for membrane targeting. Proteins from this family have been shown to play vital roles, such as in membrane trafficking and apoptosis, in eukaryotes; however, their role in prokaryotes is largely unexplored. Here, we found that the transcription of elaB is induced in the stationary phase in E. coli and stationary-phase sigma factor RpoS regulates elaB transcription by binding to the promoter of elaB Moreover, ElaB protects cells against oxidative stress and heat shock stress. However, unlike membrane peptide toxins TisB and GhoT, ElaB does not lead to cell death, and the deletion of elaB greatly increases persister cell formation. Therefore, we demonstrate that disruption of C-tail-anchored inner membrane proteins can reduce stress resistance; it can also lead to deleterious effects, such as increased persistence, in E. coliIMPORTANCEEscherichia coli synthesizes dozens of poorly understood small membrane proteins containing a predicted transmembrane domain. In this study, we characterized the function of the C-tail-anchored inner membrane protein ElaB in E. coli ElaB increases resistance to oxidative stress and heat stress, while inactivation of ElaB leads to high persister cell formation. We also demonstrated that the transcription of elaB is under the direct regulation of stationary-phase sigma factor RpoS. Thus, our study reveals that small inner membrane proteins may have important cellular roles during the stress response.
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Ma Y, Kim SS, Kwag DG, Kim SH, Ryu SH, Lee DH, So JH, Lee C, Nam MM, Park JS. Peptides Containing Multiple Disulfide-Bond Mosaic Expression in the Periplasm of Escherichia coli. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yunqi Ma
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - So-Sun Kim
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Dong-Geon Kwag
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Seo-Hyun Kim
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Seung-Ho Ryu
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Dong-Hoon Lee
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Jae-Hyeong So
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
| | - Chu Lee
- East Sea Fisheries Research Institute; National Fisheries Research and Development Institute; 1194 Haean-ro, Yeongko-myeon, Gangnenung-si Gangwon-do 210-861 Korea
| | - Myung-Mo Nam
- East Sea Fisheries Research Institute; National Fisheries Research and Development Institute; 1194 Haean-ro, Yeongko-myeon, Gangnenung-si Gangwon-do 210-861 Korea
| | - Jang-Su Park
- Department of Chemistry and Chemistry Institute of Functional Materials; Pusan National University; Busan 609-735 Republic of Korea
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Global profiling of SRP interaction with nascent polypeptides. Nature 2016; 536:219-23. [PMID: 27487212 DOI: 10.1038/nature19070] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 06/29/2016] [Indexed: 12/23/2022]
Abstract
Signal recognition particle (SRP) is a universally conserved protein-RNA complex that mediates co-translational protein translocation and membrane insertion by targeting translating ribosomes to membrane translocons. The existence of parallel co- and post-translational transport pathways, however, raises the question of the cellular substrate pool of SRP and the molecular basis of substrate selection. Here we determine the binding sites of bacterial SRP within the nascent proteome of Escherichia coli at amino acid resolution, by sequencing messenger RNA footprints of ribosome-nascent-chain complexes associated with SRP. SRP, on the basis of its strong preference for hydrophobic transmembrane domains (TMDs), constitutes a compartment-specific targeting factor for nascent inner membrane proteins (IMPs) that efficiently excludes signal-sequence-containing precursors of periplasmic and outer membrane proteins. SRP associates with hydrophobic TMDs enriched in consecutive stretches of hydrophobic and bulky aromatic amino acids immediately on their emergence from the ribosomal exit tunnel. By contrast with current models, N-terminal TMDs are frequently skipped and TMDs internal to the polypeptide sequence are selectively recognized. Furthermore, SRP binds several TMDs in many multi-spanning membrane proteins, suggesting cycles of SRP-mediated membrane targeting. SRP-mediated targeting is not accompanied by a transient slowdown of translation and is not influenced by the ribosome-associated chaperone trigger factor (TF), which has a distinct substrate pool and acts at different stages during translation. Overall, our proteome-wide data set of SRP-binding sites reveals the underlying principles of pathway decisions for nascent chains in bacteria, with SRP acting as the dominant triaging factor, sufficient to separate IMPs from substrates of the SecA-SecB post-translational translocation and TF-assisted cytosolic protein folding pathways.
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Nakahigashi K, Takai Y, Kimura M, Abe N, Nakayashiki T, Shiwa Y, Yoshikawa H, Wanner BL, Ishihama Y, Mori H. Comprehensive identification of translation start sites by tetracycline-inhibited ribosome profiling. DNA Res 2016; 23:193-201. [PMID: 27013550 PMCID: PMC4909307 DOI: 10.1093/dnares/dsw008] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/06/2016] [Indexed: 01/12/2023] Open
Abstract
Tetracycline-inhibited ribosome profiling (TetRP) provides a powerful new experimental tool for comprehensive genome-wide identification of translation initiation sites in bacteria. We validated TetRP by confirming the translation start sites of protein-coding genes in accordance with the 2006 version of Escherichia coli K-12 annotation record (GenBank U00096.2) and found ∼150 new start sites within 60 nucleotides of the annotated site. This analysis revealed 72 per cent of the genes whose initiation site annotations were changed from the 2006 GenBank record to the newer 2014 annotation record (GenBank U00096.3), indicating a high sensitivity. Also, results from reporter fusion and proteomics of N-terminally enriched peptides showed high specificity of the TetRP results. In addition, we discovered over 300 translation start sites within non-coding, intergenic regions of the genome, using a threshold that retains ∼2,000 known coding genes. While some appear to correspond to pseudogenes, others may encode small peptides or have previously unforeseen roles. In summary, we showed that ribosome profiling upon translation inhibition by tetracycline offers a simple, reliable and comprehensive experimental tool for precise annotation of translation start sites of expressed genes in bacteria.
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Affiliation(s)
- Kenji Nakahigashi
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan
| | - Yuki Takai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan
| | - Michiko Kimura
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Nozomi Abe
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan
| | - Toru Nakayashiki
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan
| | - Yuh Shiwa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Hirofumi Yoshikawa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, Tokyo 156-8502, Japan Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Barry L Wanner
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Yasushi Ishihama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hirotada Mori
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan
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Dynamic membrane protein topological switching upon changes in phospholipid environment. Proc Natl Acad Sci U S A 2015; 112:13874-9. [PMID: 26512118 DOI: 10.1073/pnas.1512994112] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A fundamental objective in membrane biology is to understand and predict how a protein sequence folds and orients in a lipid bilayer. Establishing the principles governing membrane protein folding is central to understanding the molecular basis for membrane proteins that display multiple topologies, the intrinsic dynamic organization of membrane proteins, and membrane protein conformational disorders resulting in disease. We previously established that lactose permease of Escherichia coli displays a mixture of topological conformations and undergoes postassembly bidirectional changes in orientation within the lipid bilayer triggered by a change in membrane phosphatidylethanolamine content, both in vivo and in vitro. However, the physiological implications and mechanism of dynamic structural reorganization of membrane proteins due to changes in lipid environment are limited by the lack of approaches addressing the kinetic parameters of transmembrane protein flipping. In this study, real-time fluorescence spectroscopy was used to determine the rates of protein flipping in the lipid bilayer in both directions and transbilayer flipping of lipids triggered by a change in proteoliposome lipid composition. Our results provide, for the first time to our knowledge, a dynamic picture of these events and demonstrate that membrane protein topological rearrangements in response to lipid modulations occur rapidly following a threshold change in proteoliposome lipid composition. Protein flipping was not accompanied by extensive lipid-dependent unfolding of transmembrane domains. Establishment of lipid bilayer asymmetry was not required but may accelerate the rate of protein flipping. Membrane protein flipping was found to accelerate the rate of transbilayer flipping of lipids.
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Akiyama K, Mizuno S, Hizukuri Y, Mori H, Nogi T, Akiyama Y. Roles of the membrane-reentrant β-hairpin-like loop of RseP protease in selective substrate cleavage. eLife 2015; 4. [PMID: 26447507 PMCID: PMC4597795 DOI: 10.7554/elife.08928] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/10/2015] [Indexed: 11/13/2022] Open
Abstract
Molecular mechanisms underlying substrate recognition and cleavage by Escherichia coli RseP, which belongs to S2P family of intramembrane-cleaving proteases, remain unclear. We examined the function of a conserved region looped into the membrane domain of RseP to form a β-hairpin-like structure near its active site in substrate recognition and cleavage. We observed that mutations disturbing the possible β-strand conformation of the loop impaired RseP proteolytic activity and that some of these mutations resulted in the differential cleavage of different substrates. Co-immunoprecipitation and crosslinking experiments suggest that the loop directly interacts with the transmembrane segments of substrates. Helix-destabilising mutations in the transmembrane segments of substrates suppressed the effect of loop mutations in an allele-specific manner. These results suggest that the loop promotes substrate cleavage by selectively recognising the transmembrane segments of substrates in an extended conformation and by presenting them to the proteolytic active site, which contributes to substrate discrimination.
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Affiliation(s)
| | - Shinya Mizuno
- Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Yohei Hizukuri
- Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Hiroyuki Mori
- Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Terukazu Nogi
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
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Production of disulfide bond-rich peptides by fusion expression using small transmembrane proteins of Escherichia coli. Amino Acids 2014; 47:579-87. [DOI: 10.1007/s00726-014-1892-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/03/2014] [Indexed: 01/30/2023]
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Allen RJ, Brenner EP, VanOrsdel CE, Hobson JJ, Hearn DJ, Hemm MR. Conservation analysis of the CydX protein yields insights into small protein identification and evolution. BMC Genomics 2014; 15:946. [PMID: 25475368 PMCID: PMC4325964 DOI: 10.1186/1471-2164-15-946] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/10/2014] [Indexed: 11/27/2022] Open
Abstract
Background The reliable identification of proteins containing 50 or fewer amino acids is difficult due to the limited information content in short sequences. The 37 amino acid CydX protein in Escherichia coli is a member of the cytochrome bd oxidase complex, an enzyme found throughout Eubacteria. To investigate the extent of CydX conservation and prevalence and evaluate different methods of small protein homologue identification, we surveyed 1095 Eubacteria species for the presence of the small protein. Results Over 300 homologues were identified, including 80 unannotated genes. The ability of both closely-related and divergent homologues to complement the E. coli ΔcydX mutant supports our identification techniques, and suggests that CydX homologues retain similar function among divergent species. However, sequence analysis of these proteins shows a great degree of variability, with only a few highly-conserved residues. An analysis of the co-variation between CydX homologues and their corresponding cydA and cydB genes shows a close synteny of the small protein with the CydA long Q-loop. Phylogenetic analysis suggests that the cydABX operon has undergone horizontal gene transfer, although the cydX gene likely evolved in a progenitor of the Alpha, Beta, and Gammaproteobacteria. Further investigation of cydAB operons identified two additional conserved hypothetical small proteins: CydY encoded in CydAQlong operons that lack cydX, and CydZ encoded in more than 150 CydAQshort operons. Conclusions This study provides a systematic analysis of bioinformatics techniques required for the unique challenges present in small protein identification and phylogenetic analyses. These results elucidate the prevalence of CydX throughout the Proteobacteria, provide insight into the selection pressure and sequence requirements for CydX function, and suggest a potential functional interaction between the small protein and the CydA Q-loop, an enigmatic domain of the cytochrome bd oxidase complex. Finally, these results identify other conserved small proteins encoded in cytochrome bd oxidase operons, suggesting that small protein subunits may be a more common component of these enzymes than previously thought. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-946) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Matthew R Hemm
- Department of Biological Sciences, Towson University, Towson 21252MD, USA.
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A DNA damage-induced, SOS-independent checkpoint regulates cell division in Caulobacter crescentus. PLoS Biol 2014; 12:e1001977. [PMID: 25350732 PMCID: PMC4211646 DOI: 10.1371/journal.pbio.1001977] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/17/2014] [Indexed: 01/26/2023] Open
Abstract
A study of the bacterium Caulobacter crescentus reveals an SOS-independent DNA damage response pathway that acts via a novel cell division inhibitor, DidA, to suppress septum synthesis. Cells must coordinate DNA replication with cell division, especially during episodes of DNA damage. The paradigm for cell division control following DNA damage in bacteria involves the SOS response where cleavage of the transcriptional repressor LexA induces a division inhibitor. However, in Caulobacter crescentus, cells lacking the primary SOS-regulated inhibitor, sidA, can often still delay division post-damage. Here we identify didA, a second cell division inhibitor that is induced by DNA damage, but in an SOS-independent manner. Together, DidA and SidA inhibit division, such that cells lacking both inhibitors divide prematurely following DNA damage, with lethal consequences. We show that DidA does not disrupt assembly of the division machinery and instead binds the essential division protein FtsN to block cytokinesis. Intriguingly, mutations in FtsW and FtsI, which drive the synthesis of septal cell wall material, can suppress the activity of both SidA and DidA, likely by causing the FtsW/I/N complex to hyperactively initiate cell division. Finally, we identify a transcription factor, DriD, that drives the SOS-independent transcription of didA following DNA damage. Cells have evolved sophisticated mechanisms for repairing their DNA and maintaining genome integrity. A critical aspect of the repair process is an arrest of cell cycle progression, thereby ensuring that cell division is not attempted before the genome has been repaired and fully duplicated. Our paper explores the molecular mechanisms that underlie the inhibition of cell division following DNA damage in the bacterium Caulobacter crescentus. For most bacteria, the primary, and only mechanism previously described involves the SOS response, in which DNA damage induces cleavage of the transcriptional repressor LexA, driving induction of a battery of genes that includes an inhibitor of cell division (sulA in E. coli and sidA in Caulobacter). Here, we report that Caulobacter cells have a second, SOS-independent damage response pathway that induces another division inhibitor, didA, which works together with sidA to block cell division following DNA damage. We also identify the damage-sensitive transcription factor responsible for inducing DidA. Finally, our study demonstrates that DidA and SidA inhibit cell division in an atypical manner. Many division inhibitors in bacteria appear to inhibit the protein FtsZ, which forms a ring at the site of cell division. DidA and SidA, however, target a trio of proteins, FtsW/I/N, that help synthesize the new cell wall that will separate the daughter cells (the septum). In sum, our work expands our understanding of how bacterial cells respond to DNA damage and the mechanisms by which they regulate cell division.
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Chen H, Luo Q, Yin J, Gao T, Gao H. Evidence for the requirement of CydX in function but not assembly of the cytochrome bd oxidase in Shewanella oneidensis. Biochim Biophys Acta Gen Subj 2014; 1850:318-28. [PMID: 25316290 DOI: 10.1016/j.bbagen.2014.10.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/25/2014] [Accepted: 10/06/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Cytochrome bd oxidase, existing widely in bacteria, produces a proton motive force by the vectorial charge transfer of protons and more importantly, endows bacteria with a number of vitally important physiological functions, such as enhancing tolerance to various stresses. Although extensively studied as a CydA-CydB two-subunit complex for decades, the complex in certain groups of bacteria is recently found to in fact consist of an additional subunit, which is functionally essential. METHODS We investigated the assembly of the CydA-CydB complex using BiFC. We investigated the function of CydX using mutational analysis. RESULTS CydX, a 38-amino-acid inner-membrane protein, is associated with the CydA-CydB complex in Shewanella oneidensis, a facultative anaerobe renowned for its respiratory versatility. It is clear that CydX is neither required for the in vivo assembly of the CydA-CydB complex nor relies on the complex for its translocation and integration into the membrane. The N-terminal segment (1-25 amino acid residues) and short periplasmic overhang of CydX, with respect to functionality, are important whereas the remaining C-terminal segment is rather flexible. CONCLUSION Based on these findings, we postulate that CydX may function by positioning and stabilizing the prosthetic hemes, especially heme d in the CydA-CydB complex although a role of participating in catalytic reaction is not excluded. GENERAL SIGNIFICANCE The work provides novel insights into our understanding of the small subunit of the cytochrome bd oxidase.
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Affiliation(s)
- Haijiang Chen
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qixia Luo
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jianhua Yin
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Tong Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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Orfanoudaki G, Economou A. Proteome-wide subcellular topologies of E. coli polypeptides database (STEPdb). Mol Cell Proteomics 2014; 13:3674-87. [PMID: 25210196 DOI: 10.1074/mcp.o114.041137] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cell compartmentalization serves both the isolation and the specialization of cell functions. After synthesis in the cytoplasm, over a third of all proteins are targeted to other subcellular compartments. Knowing how proteins are distributed within the cell and how they interact is a prerequisite for understanding it as a whole. Surface and secreted proteins are important pathogenicity determinants. Here we present the STEP database (STEPdb) that contains a comprehensive characterization of subcellular localization and topology of the complete proteome of Escherichia coli. Two widely used E. coli proteomes (K-12 and BL21) are presented organized into thirteen subcellular classes. STEPdb exploits the wealth of genetic, proteomic, biochemical, and functional information on protein localization, secretion, and targeting in E. coli, one of the best understood model organisms. Subcellular annotations were derived from a combination of bioinformatics prediction, proteomic, biochemical, functional, topological data and extensive literature re-examination that were refined through manual curation. Strong experimental support for the location of 1553 out of 4303 proteins was based on 426 articles and some experimental indications for another 526. Annotations were provided for another 320 proteins based on firm bioinformatic predictions. STEPdb is the first database that contains an extensive set of peripheral IM proteins (PIM proteins) and includes their graphical visualization into complexes, cellular functions, and interactions. It also summarizes all currently known protein export machineries of E. coli K-12 and pairs them, where available, with the secretory proteins that use them. It catalogs the Sec- and TAT-utilizing secretomes and summarizes their topological features such as signal peptides and transmembrane regions, transmembrane topologies and orientations. It also catalogs physicochemical and structural features that influence topology such as abundance, solubility, disorder, heat resistance, and structural domain families. Finally, STEPdb incorporates prediction tools for topology (TMHMM, SignalP, and Phobius) and disorder (IUPred) and implements the BLAST2STEP that performs protein homology searches against the STEPdb.
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Affiliation(s)
- Georgia Orfanoudaki
- From the ‡Institute of Molecular Biology and Biotechnology-FoRTH and §Department of Biology-University of Crete, P.O. Box 1385, Iraklio, Crete, Greece
| | - Anastassios Economou
- From the ‡Institute of Molecular Biology and Biotechnology-FoRTH and §Department of Biology-University of Crete, P.O. Box 1385, Iraklio, Crete, Greece; ¶Laboratory of Molecular Bacteriology; Rega Institute, Department of Microbiology and Immunology, KU Leuven, Herrestraat 49, B-3000 Leuven, Belgium
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Abstract
Many viruses encode short transmembrane proteins that play vital roles in virus replication or virulence. Because many of these proteins are less than 50 amino acids long and not homologous to cellular proteins, their open reading frames were often overlooked during the initial annotation of viral genomes. Some of these proteins oligomerize in membranes and form ion channels. Other miniproteins bind to cellular transmembrane proteins and modulate their activity, whereas still others have an unknown mechanism of action. Based on the underlying principles of transmembrane miniprotein structure, it is possible to build artificial small transmembrane proteins that modulate a variety of biological processes. These findings suggest that short transmembrane proteins provide a versatile mechanism to regulate a wide range of cellular activities, and we speculate that cells also express many similar proteins that have not yet been discovered.
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Affiliation(s)
- Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520;
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Abstract
Small proteins, here defined as proteins of 50 amino acids or fewer in the absence of processing, have traditionally been overlooked due to challenges in their annotation and biochemical detection. In the past several years, however, increasing numbers of small proteins have been identified either through the realization that mutations in intergenic regions are actually within unannotated small protein genes or through the discovery that some small, regulatory RNAs encode small proteins. These insights, together with comparative sequence analysis, indicate that tens if not hundreds of small proteins are synthesized in a given organism. This review summarizes what has been learned about the functions of several of these bacterial small proteins, most of which act at the membrane, illustrating the astonishing range of processes in which these small proteins act and suggesting several general conclusions. Important questions for future studies of these overlooked proteins are also discussed.
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Affiliation(s)
- Gisela Storz
- Cell Biology and Metabolism Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-5430;
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Marvin DA, Symmons MF, Straus SK. Structure and assembly of filamentous bacteriophages. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 114:80-122. [PMID: 24582831 DOI: 10.1016/j.pbiomolbio.2014.02.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 02/09/2014] [Indexed: 12/24/2022]
Abstract
Filamentous bacteriophages are interesting paradigms in structural molecular biology, in part because of the unusual mechanism of filamentous phage assembly. During assembly, several thousand copies of an intracellular DNA-binding protein bind to each copy of the replicating phage DNA, and are then displaced by membrane-spanning phage coat proteins as the nascent phage is extruded through the bacterial plasma membrane. This complicated process takes place without killing the host bacterium. The bacteriophage is a semi-flexible worm-like nucleoprotein filament. The virion comprises a tube of several thousand identical major coat protein subunits around a core of single-stranded circular DNA. Each protein subunit is a polymer of about 50 amino-acid residues, largely arranged in an α-helix. The subunits assemble into a helical sheath, with each subunit oriented at a small angle to the virion axis and interdigitated with neighbouring subunits. A few copies of "minor" phage proteins necessary for infection and/or extrusion of the virion are located at each end of the completed virion. Here we review both the structure of the virion and aspects of its function, such as the way the virion enters the host, multiplies, and exits to prey on further hosts. In particular we focus on our understanding of the way the components of the virion come together during assembly at the membrane. We try to follow a basic rule of empirical science, that one should chose the simplest theoretical explanation for experiments, but be prepared to modify or even abandon this explanation as new experiments add more detail.
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Affiliation(s)
- D A Marvin
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
| | - M F Symmons
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - S K Straus
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
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